Wednesday

How to choose the best 18650 rechargeable battery for flashlight?
Which one last the longest?
It is one great question for outdoor enthusiasts ( AKA flashaholics)

I always find reviews and tests from folks who are new to 18650 batteries genuine, and most entertaining.
Why?
Average flashlight user doesn't know battery test tricks, and will usually show us a real life 18650 battery performance. Which is very good to get real review data.
They simply charge those cells fully, run them all in the same flashlight (that is important part of this review)...
Lithium-ion rechargeable battery that provides the longest run time is the winner.
Simple as that.
This video shows which li-ion fully charged battery will run the longest in LED flashlight.

Samsung 25R green (very popular battery in vaping and flashlight community)LG HG2 (good high drain cell, but not many info on flashlight real life usage)
or Orbtronic ORB3400 (well-known battery made for flashlights only)

Saturday

Let's start with LG HG2 battery review - performance test.LG 18650HG2 18650 battery li-ion (lithium-ion) is made and distributed by well-knownLG Chem manufacturer located in South Korea.LG Chem is also known as LG Chemical, the largest chemical company in S. Korea.Quick Fact:The Ford Focus Electric, Volvo V60 & Chevrolet Volt are powered by LG batteries.

Basic info

Specifications:

Model: INR18650HG2

Capacity: 3000mAh

Released: 2014

Product Classification: Cylindrical rechargeable lithium ion battery

Intended use (application): Power Tools

Max. Constant Current 20 A (20000 mA)

Cycle Life @ 10A: 300 cycles at 10 A

Cycle Life @ 20A: 200 cycles at 20 A

Initial AC impedance: less (or equal) than 20 mΩ

Dimensions: Diameter Max 18.5mm, Height Max 65.2mm

Weight: Max 47g

Operating temperature (battery cell surface temp.): -20 ~ 75 ℃

Lower limit (cutoff) discharge voltage under load: 2.5V

Yes, that is correct this cell is made for Power Tools.Unprotected 18650 batteries are not intended to be used in vape mod (e-cig) devices, or flashlights.Why?That is because each 18650 battery (or battery pack) should have properly designed and installed electronic protection circuit (per manufacturer recommendation). Incidentally, LG HG2 became one of the most popular 18650 vape battery cell. That is one of the reasons I picked this particular battery for this review & test.

Review-Test 1 : Capacity @ 15A Continuous Discharge INR18650HG2

Voltage vs Capacity:Let's see how much capacity we can get from LG HG2 under 15 Amp constant (continuous) discharge load. The test battery is fully charged to 4.2V, and discharged to 2.5V. Click on the picture below to see full-size battery discharge graph with the (green) capacity curve.

15A continuous discharge is somewhere in between two max. discharge values provided by manufacturer-LG for this 18650 li-ion battery cell. 10A for approximately 300 cycles, and 20A for approximately 200 cycles.LG HG2 total capacity under 15A is 2835mAh which is very good for this type of battery under 15 Amp continuous discharge rate.

Voltage drop/sag

The green line in the graph above visually represents what is happening with the battery voltage once power button on your device is pressed.It is called Voltage Drop.Voltage drop value greatly depends on:

Discharge Load. For this part of the test, it is: 15A Continuous high current drain

Internal battery resistance

18650 Li-ion batteries (all lithium based batteries) have different internal resistance values. Internal resistance depends on build quality (quality control), design (internal, and external), chemistry modifications, a number of cycles, and age of battery cell.

Review-Test 2 : Capacity @ 20A Continuous Discharge INR18650HG2

LG HG2 Amp limit (according to official manufacturer datasheet) is 20A Continuous current load.
Let's see how this high drain battery can handle 20 Amp

Click on the picture below to expand discharge graph with the capacity curve:

20 Amp continuous discharge graph

This battery can handle 20 Amp of continuous discharge without problems, but the question is: should you use LG INR18650HG2 @ 20A?
In my opinion, you should not run it at 20 Amp too often.
Why you should not run 18650 battery at full (max) amp load (limit)?
If you read manufacturer datasheet carefully you will see that discharging this li-ion 18650 battery with the very high load will drastically reduce the total number of charge/discharge cycles (lifespan).

Is it good for LED Flashlight?

Luckily LED Flashlights (even high-power 2016 models) do not require such a high current to work at the full power level (e.g. turbo mode).
I will test this (officially rated by LG) 3000mAh battery at lower currents (more suitable for flashlights) just to see how it behaves (voltage drop should not be as deep as @ 20A, and 15A discharge) under lower currents. I think we will be able to get more usable capacity out of it at lower loads. Scroll down to see the test at 5A load.

Is it good for vape mod (electronic cigarette)?

Some new, and inexperienced battery testers are trying to rate li-ion batteries for vape mod users based on continuous discharge tests, and temperature only.
This is definitely the wrong way to test, and recommend (not recommend) batteries for vaping devices.
Lack of experience and basic knowledge about li-ion technology is the biggest problem in the vaping community.

When we want to test 18650 li-ion battery for vape devices - pulse test is the only way to do it. Pulse discharge test is very close to what is really happening with battery cell when it is inside your box mod, or any e-cig device (mech mod, etc.).
I will perform pulse (burst) tests as well, stay tuned.

Using only battery temperature level to rate li-ion battery for vape mods is wrong and provides false (inaccurate) ratings:

Measuring temperature and rating li-ion battery based on continuous current discharge have nothing to do with vapers. Or in simple words: it gives you wrong information about (real) battery capabilities.

If battery tester provides ratings based only on temperature then always ask for full temperature graph to be revealed (alongside discharge curve).

Why?

Because, a temperature of that battery after 0.5 to 2 minutes under high current load, is much lower than temperature after 4 to 5 minutes under that same high current load.

Advice for vapers:
If you see battery tests ratings based on temperature, and temperature graph (curve showing temperature progress) is hidden, then something is wrong with that test data.
Always ask: Why temperature graph is hidden?
I will provide more tests with temperature data included. These are just basic continuous discharge tests - to see how this cell can handle various constant current loads. So far so good.

Review-Test 3 : Capacity @ 5A Continuous Discharge INR18650-HG2

Let's continue with LG HG2 review. This part of the test will be dedicated to continuous discharge at 5A (5000mA) constant current. From fully charged 18650 battery (full charge = 4.2V)] to the lowest voltage level we can go with this particular li-ion cell - which is 2.5V.
Click on discharge graph below to expand image - full size.

This is very interesting, and useful interactive chart - hover your mouse over red line (temperature), or blue line (voltage), and you will be able to see:

Battery temperature - red

Battery Voltage - blue

Time (in seconds)

Current load is 10A constant value

Remember:
There is no 18650 30A 3000mAh battery in existence
There is no 35A or 40A 2100mAh or 2600mAh 18650 battery in existence
There is no 20A 3100mAh or 3200mAh or 3500mAh 18650 battery in existence

Safety is the only reason I am doing this.
Li-ion battery can be very dangerous when fake rating and bad seller/tester meet together.

Friday

As many of you already know Panasonic is one of the main suppliers for Tesla's 18650 battery pack (Model S).
Very interesting news is that Panasonic is ready to do anything to speed up Tesla's "Gigafactory" project.
Tesla will implement existing, and already well developed Panasonic's 18650 battery manufacturing technology.
Gigafactory (located in Nevada) will be the first lithium-ion manufacturing plant of this size in USA.

Tuesday

Lithium-ion battery technology is very popular among electric automakers. One of the biggest brands that is currently using Li-ion cells to improve mileage is German BMW.
It seems that this time Samsung SDI battery manufacturer is BMW's nr.1 choice.

Monday

18650 battery test-reviews is what I will start doing from the next week.

It will ne very interesting to see how 18650 batteries behave under different working conditions.

These bench tests and reviews will include:

Visual discharge graph (curve) at various continuous and pulse current loads.

Battery Amp limit.

Real capacity (cell will be discharged from full charge to the lowest voltage discharge cutoff limit).

Working temperatures during discharge in real time.

Original Battery Specs - datasheet from manufacturers.

You will be able to see the actual performance of the battery cell (in various situations), that you might be using already or that you would like to buy somewhere online but not sure about performance.

Why am I doing this?

Answer: Safety!

It is getting out of control.

Flashlight community is pretty much safe, because 99.9% of today's LED flashlights are running on 18650 Protected batteries.

The lithium-ion safety risk is the highest in vape (electronic cigarette) community that is growing very fast.

Lack of proper li-ion 26650,18650 battery knowledge is the biggest enemy for average vape (ecig) end user (vaper).

To make this already dangerous situation for vaping users even more risky we can see more, and more companies (usually Chinese) releasing unprotected vape 18650, and 26650 batteries with exaggerated Amp limit rating numbers. Sometimes 500% over actual battery Amp rating.

It seems that box mod e-cig batteries are becoming good source of income for individuals who represent themselves as "independent" battery testers.

I will talk more about these "unbiased" battery tests too, and what tricks they use to make battery performance bad, or good.

Just some of the 18650 batteries that will be tested with very accurate (lab calibrated) computer battery analyzer:

LG HG2

LG HE2 and HE4

LG HD2 and HD2C

LG HB6

Samsung 30Q , 25R, 20R

Sony VTC4

Sony VTC5, VTC5A

Sony VTC6

Panasonic NCR18650GA, NCR18650B, NCR18650PF, UR18650NSX

Some very good, and some really really bad, and dangerous rewraps will be tested as well.

Many more batteries will be tested and posted on this blog. This is just a beginning...

Tuesday

18 - The first two digits "18" stand for li-ion battery diameter in millimeters. In this case width of the battery is 18mm (millimeters).

65 - The third, and fourth digit stand for length in millimeters. That would be 65mm.

0 ? - For those who want to know why zero is there, this is how battery manufacturers calculate batt. length: 650 divided by 10 is 65mm. Since we are simple people we will forget about zero for now.

18mm by 65mm - 18650

Metric system (millimeters) is used almost always when we see
li-ion battery with numbers like:

18650
18500
16340

16650

14500

26650

Above are the most common li-ion battery sizes. So, next time when you see 18650 battery you will know for sure meaning of all these numbers.

Let's see what we have learned today.

What is 26650?

26mm - diameter

65mm - length

Battery dimensions in a real world can, and will vary.
Important:
These measurements are for bare Li-ion cells only (also called "unprotected" or "flat top").
If you see "PROTECTED" printed next to 18650, 16340, 14500, 26650 ... that means that external protection circuit board is welded to the bottom of the bare cell, and flat wire is added to the side of the cell.Because of added external protection protected Li-ion batteries are 2.5mm to 3mm longer, and can be 0.5mm wider than bare Li-ion cells.
I will explain what Protected Li-ion battery is in one of my next posts.

By the way, 16340 rechargeable li-ion battery is also called RCR123. It is the same size as CR123A primary (non-rechargeable) cell. First letter "R" means rechargeable.
And again, if word "Protected" is printed next to 16340 (or RCR123), battery will be longer than regular CR123A by 2.5mm to 3mm.

14500 Li-ion is the same size as AA battery, but it should never be used as a replacement for regular (Ni-Mh) AA battery. Why? Well, stay tuned I will keep posting some interesting stuff.

Example:
As you can see from this photo battery size will vary slightly. This is one bare unprotected 18650 battery. Flat top.Protected 18650 (or any 26650, 16340, 16650,14500 ...) lithium-ion batteries will be approximately 2.5-3 mm longer, and 0.5 mm-0.6 mm wider in diameter.